An unmanned drone aircraft is flying over the vast Rim Fire near Yosemite National Park and sending back real-time data to firefighters on hot spots and movement of the blaze, fire officials say.
The National Guard Predator drone launched Wednesday from an airfield in Southern California and can remain airborne for 22 hours at a time.
Daniel Berlant, spokesman for California's state fire agency, says the military drone is being used in its biggest firefighting test to date and has provided commanders with real-time images and information on fire activity near and inside Yosemite.
"Because the fire is so large … we're hoping that new technology will allow us to better deploy our resources,'' Berlant said.
The U.S. Forest Service said in a statement that the aircraft "will identify where fire activity is located and how it is moving, including locating and identifying spot fires which will improve the ability to protect life, property, and natural resources."
The Rim Fire has grown to 311 square miles in less than two weeks, and officials say it is 32% contained. More than 4,900 firefighters are battling the blaze, aided by retardant-dropping helicopters and tanker airplanes.
Firefighters got a break with relatively cooler temperatures and moist air this week, but hotter weather is forecast, just as the Labor Day weekend brings increased visitors to wilderness areas and parks around the country.
This fire is one of 10 burning around California, with nearly 10,000 firefighters battling them, With more than two months left in the normal fire season in California, officials are worried about more big fires like this one flaring up.
"This is one of the last weekends for families to go out camping and recreating before summer ends. While conditions remain ripe for fires … we're trying to urge everybody to be extra cautious outdoors,'' he said.
Fire officials estimate that the Rim Fire can be contained no sooner than Sept. 10 and that portions will continue to burn beyond that date.
The remotely piloted drone, which is the size of a small Cessna, has helped firefighters by shouldering the burden normally carried out by helicopters, which must be refueled every two hours.
The MQ-1 unmanned aircraft is from the California Air National Guard's 163rd Reconnaissance Wing from Riverside and is operating from Victorville Airport. It flew over mostly unpopulated areas on its 300-mile flight to the Rim Fire
''The drone is providing data directly back to the incident commander, allowing him to make quick decisions about which resources to deploy and where,'' Berlant said.
Officials were careful to point out the images are being used only to aid in the effort to contain the fire. Outside the fire area, it will be escorted by a manned aircraft.
In 2009, a NASA Predator equipped with an infrared imaging sensor helped the U.S. Forest Service assess damage from a fire in Angeles National Forest. In 2008, a drone capable of detecting hot spots helped firefighters assess movement of a series of wildfires stretching from Southern California's Lake Arrowhead to San Diego.
Contributing: William M. Welch in Los Angeles; the Associated Press